Atomically Precise Manufacturing — Part 1
As atom-by-atom assembly becomes more feasible, we explore some of the implications this may have on our current industries
Intro
Atomically Precise Manufacturing (APM) is a means of production in which individual atoms are arranged and placed in specific locations relative to other atoms. Do this enough times and 3D structures can be assembled from digital instructions. The grand vision for this is to give us the ability to assemble any object imaginable, atom by atom, in a similar fashion as the matter compilers in Neal Stephenson’s novel Diamond Age, or the replicators in Star Trek. Though we are still far from assembling physical objects of that size or complexity, there have been substantial advances in that direction, with potential for some near-term commercial opportunities.
The ability to place atoms with such precision provides the ability to create materials and structures largely devoid of defects and impurities. Imagine perfect graphene sheets, or 100% pure molecular compounds or pharmaceuticals all built up atom by atom. Or when desired, impurities could be placed exactly where they are needed to dope or modify the crystalline structure of metal alloys or semiconductor materials.
A simple example of APM that has generated headlines numerous times over the last 40 years is nano-scale text, the writing or recording of visual information on a physical substrate at the nanometer scale. In 1959 Richard Feynman gave a lecture (which later was transcribed and came to be called “There’s Plenty of Room at the Bottom”) in which he pondered the direct manipulation of individual atoms of matter, and asked “Why can’t we write the entire 24 volumes of the Encyclopedia Britannica on the head of a pin?”. Although he was ahead of his time, text of comparable size has been successfully generated numerous times since then, including this nano bible in which 1.2 million hebrew letters were legibly written on a tiny chip of silicon the size of a grain of sugar, created in 2015. A feat like this naturally prompts a commercial inquiry about the ability to make ultra-dense, ultra-small data storage devices. There are even aspirations of storing digital bits (1’s and 0’s) as single atoms, which is now being actively pursued. Imagine a 1 being the presence of a gold atom on a silicon substrate, and a 0 being an absence of a gold atom. Single-atom information storage representing the smallest imaginable means of physical data storage, a massive improvement on the 1 million metal atoms that make up a single digital bit on today’s magnetic hard drives.
Among the broad set of other applications and potential benefits of APM are:
- Reaching the end of Moore’s Law
- Producing practical quantum computers
- Commercializing innovations that have been shelved because they are too costly to mass produce
- Benefits to renewable energies
- Ability to create stronger and more exotic materials
We will discuss each of these in more detail below
History
Historically, it has been observed that advancements in human civilization are often closely tied to the development of improved tools that provide a stepwise increases in precision. We started by using handmade, stone tools and progressed to bronze and iron tools made in furnaces, all of which operated at size scales and precision levels we could hold with our bare hands and see with the naked eye. In the 1800s, we mechanized the manufacture of tools with technologies like steam power, and metal alloys with higher purities, allowing us to build tools with precisions of less than a millimeter. In the early 1900s the preceding advancements coupled with the use of electricity, gave us precision at a micrometer level, and with this came the ability to use and repetitively produce interchangeable parts. From the 1950s onwards, improvement in optics and technologies like photolithography gave us precision at the nanometer scale, leading to the semiconductor and integrated circuit revolution through automated manufacturing. These processes have improved further still since then, giving us some forms of sub-nanometer precision. For reference, the physical diameter of atoms is often described with the SI length unit of the Ångstrom, which is 1/10 of a nanometer. A hydrogen atom is on the order of 1 Ångstrom in diameter, a carbon atom is about 1.5 Ångstrom, and much larger metal atoms can get up to 5 Ăngstrom. So atoms will be in the range of 0.1–0.5 nanometers in diameters depending on the element.
The next step in improving the precision of our tooling is to go to the atomic level. When we get there, the positive impact on humans could be greater than all the preceding developments combined. The below graphic from the International Journal of Extreme Manufacturing depicts the precision advancements described above:
Reaching the end of Moore’s Law
Moore’s Law, which states that the number of transistors on a chip will double every two years, is not actually a law; it is simply an observation of a historical trend that had some predictive value. Its reliability for the past 55 or so years has heralded vast advances in computer technology. However, we are running out of ways to put more transistors on chips with existing processes.
In order to continue the trend of circuit miniaturization, we will soon need to begin assembling circuit components at the scale of a few atoms per component if we want to achieve a higher density of chip circuitry than we have today. In the entry entitled “Digital atomic scale fabrication an inverse Moore’s Law — A path to atomically precise manufacturing” in Volume 1 of Micro and Nano Engineering, the authors encapsulate what is happening:
“manufacturing precision is one of the primary rate limiting factors on human technological progress…. We are clearly running into the quantized nature of atomic-scale matter. This… is at the heart of the demise of the remarkable exponential progress of Moore’s Law and… presents a major problem in technology advances… because one of the principal ways of advancing technology has been to improve manufacturing precision, and there is not another 5 orders of magnitude improvement in manufacturing precision to be had in the next 100 years…. [APM can create] a new exponential trend in manufacturing that can effectively replace Moore’s Law and give us a different path to technology advancements in areas more general than information processing”
In essence, the implications of APM are that we will soon reach the true end of Moore’s Law as components (and digital information storage) reach the smallest possible unit of construction, a single atom. This will require a new atomic paradigm that goes far beyond putting more transistors on ever smaller chips. We are hitting our size limits using traditional manufacturing techniques; and we will need to think differently if we would like to continue the pace of technological advancement that we have grown accustomed to over the last 100 years.
Producing practical quantum computers
A promising way for us to create quantum computers is by leveraging the advances of the semiconductor industry in placing transistors on chips. The difference is that with quantum computers we instead place Phosphorus atoms in silicon and encode quantum information in the atom’s ‘nuclear spin.’ Nuclear spin is the ‘total angular momentum of a nucleus… [and] each nuclear spin is a nuclear magnetic moment which produces magnetic interactions with its environment’ (Georgia State University). Basically, we can encode a qubit, or unit of quantum information, in the magnetic interactions that occur between these P atoms and their environment. However, it is critical that these atoms be precisely placed since scaling up the placement of these P atoms in silicon “generally relies on uniformity of control of qubits and their interactions. Even small variations at the level of one lattice site for qubits based on single or multiple dopant atoms can significantly affect the design and control of logical operations” (NPJ, Framework for atomic-level characterisation of quantum computer arrays by machine learning). Thus, we need to have highly precise systems for placing these atoms in order to scale up quantum computing.
While the semiconductor industry’s transistor placement advancements are helpful in putting a single qubit in silicon, they have their limitations as the process is scaled up. This is because while the industry has gotten adept at fitting more and more transistors on chips, the relative precision with which the transistors are placed has gotten worse over the last twenty years: “Two decades ago the relative precision was roughly +/− 5%. It is closer to +/− 10% today” (ScienceDirect, Digital atomic scale fabrication an inverse Moore’s Law — A path to atomically precise manufacturing). While this level of relative precision is acceptable for products that use semiconductors, it is not acceptable for placing an array of P atoms for the use case of quantum computing. A reliable, high-throughput means of placing these atoms with atomic precision would allow for more scalable manufacturing of quantum computers.
It’s also worth noting that the semiconductor industry has been held back by poor relative precision of current manufacturing processes and could stand to benefit from the ability to place transistors with atomic precision: “This poor relative precision has forced the semiconductor industry to avoid taking advantage of the emerging properties of materials at the nanoscale, because those properties depend very sensitively on the size. Because semiconductor manufacturing processes lack good relative precision, digital electronics cannot take advantage of these emerging properties because they cannot control them” (ScienceDirect, Digital atomic scale fabrication an inverse Moore’s Law — A path to atomically precise manufacturing). New advances in APM for quantum computing or otherwise are thus unlikely to come from the semiconductor industry; since semiconductors are where the advancements in nanomanufacturing/APM have been made historically, many of the tools being used in other applications at research facilities came out of the semiconductor industry and have the same poor relative precision. Thus we may need an entirely new generation of equipment to be developed before widespread APM will be possible.
There are a number of interesting companies in the quantum computing space. HyperLight is a Massachusetts based maker of circuits with use cases in quantum computing, and NuCrypt, which provides quantum optical instrumentation, are both working on a quantum network in the Chicago Area, in partnership with the DOE, Northwestern, FERMILAB and others; the network will use “a combination of cutting-edge quantum and classical technologies to transmit quantum information and will be designed to coexist with classical networks” (FERMILAB). Xanadu is a Toronto based company founded in 2016 that leverages quantum silicon photonic chips in existing hardware to create quantum computers and allows users to access these computers in the cloud. The CEO of Australia based Silicon Quantum Computing, Michelle Simmons, has said, “We have developed atomically-precise fabrication techniques that are uniquely suited to building a quantum computer” (Innovation AUS). In September 2020, Silicon Quantum Computing hired John Martinis, a UCSB physics professor who established Google’s Quantum hardware group: “Google’s former top quantum scientist John Martinis, who helped the tech giant achieve quantum supremacy, has joined Australian startup Silicon Quantum Computing, lending significant validation for its approach to the technology” (Innovation AUS). IonQ, which is working on a general purpose quantum computer using a trapped ion, and Atom Computing, which is working on a quantum computer in which atoms are controlled optically and without wires, are both names to keep an eye on in this space as well.
Commercializing innovations that have been shelved because they are too costly to mass produce
One of my favorite pastimes is reading science articles detailing the new advances in technology that happen every day in research labs across the world. Usually they say something like “Researchers make new wonder material” or “Researchers find new way to make xxxxxx”. The challenge for us as a firm, and me in particular is finding the stories that actually represent an opportunity for commercialization. There are countless materials or devices that are scientifically feasible, but we can’t quite figure out how to make them using existing fabrication techniques. Or maybe we have prototypes that can be made one at a time at a cost of $millions per unit, but there is no practical means to reproduce them in a quantity to allow commercialization. An example can be found in the nanobot designs referred to as Respirocytes, “an artificial red blood cell which could store 236 times the oxygen as a normal red blood cell” (ScienceDirect, Digital atomic scale fabrication an inverse Moore’s Law — A path to atomically precise manufacturing). This is essentially a nanobot that circulates in the bloodstream of living things and emulates a red blood cell. The physics behind this suggests that this is viable, but we do not yet have the ability to build something that relies on such a level of atomic precision. In regards to these, the ScienceDirect article referenced above notes that, “Texas Instruments produced a large number of prototype devices that had excellent device characteristics including a simple integrated circuit that operated satisfactorily at room temperature but failed to develop successful products. The reason… quantum resonant tunneling electronics, and a number of other potentially very complex and useful nanotechnology products that have been either designed or even prototyped have not made it to market is because we lack the manufacturing precision to mass produce them.” This means that there is a whole world of useful nanotechnology products we could create or have created prototypes for that are sitting on the shelf because our manufacturing processes are not precise enough to create them at scale — APM could allow the world to experience the power of these innovations by providing the tools to shape matter into any form we can imagine.
Benefits to renewable energies
Another benefit of APM that goes hand in hand with improved nanomanufacturing is improved solar energy production. As is the case with putting more transistors on a chip, putting more photovoltaic elements on a panel improves performance. If we can manufacture solar cells with nanoscale precision, we can modify the surface structure to capture more light and in a broader IR spectrum to improve that performance still further. Hammering home this point in his blog post Making Room at the Bottom, Strad Slater notes that “Atomic precision would allow us to make solar cells much more efficient by increasing their overall surface area and by creating materials that could contain the energy lost from heat at a much higher rate then today’s do.” And it’s possible that multi-junction solar cells could be more efficiently manufactured using the bottom-up processes that APM promises.
There are also theoretical possibilities for creating better carbon capture materials that are more selective for CO2, and require less energy to regenerate or recover. And adsorbant materials of this nature could be tuned to capture almost any environmental toxin or contaminant; or to harvest desirable compounds as well, such as condensing atmospheric water in arid desert regions.
Ability to create stronger and more exotic materials
By constructing materials atom by atom from the bottom-up, we will be able to produce so-called metamaterials that do not exist in nature and cannot be made by any known means. This is especially true when we consider the implications of materials made without impurities or defects. Science writers sometimes use the adage about new materials being stronger than steel; but in truth our steel is not nearly as strong as it could be if it were properly arranged at the atomic level. Steel is full of microcracks, voids, and unwanted contaminants that compromise the strength. Today we mix molten metals together in a vat, and rely on the natural tendencies of these atoms to arrange themselves as the mixture cools. If we instead could make alloys by stacking individual metal ions in exactly the right proportions the physical properties could be vastly improved, or custom tailored for specific applications. Remember that carbon atoms assembled one way produces the soft graphite inside pencils, while the same carbon atoms stacked another way produces diamonds. This same carbon can also be assembled into graphene and carbon nanotubes, which are thought to be the strongest materials that can possibly be produced, but that today are very difficult to make without defects. As I discussed in a previous post, I believe that graphene will change the world once we can make it reliably with atomic precision.
Being able to assemble materials at the atomic level will open vast doors of possibility for our materials science to advance. We can expect to see massive increases in the number of new metamaterials coming out of labs as researchers begin experimenting with new combinations of materials and crystalline structures that could not be grown naturally, but can be assembled atom by atom. In truth, we will probably see more new material composites become available in the next 100 years than the sum total of all materials invented or isolated by mankind in the last 10,000 years.
We are already able to produce certain materials using bottom-up manufacturing processes such as chemical vapor deposition and scanning tunneling electron microscopes. We will talk about these existing methods in detail in part 2 of this paper, along with our current limits and where things are trending. We will also discuss some of the ramifications and concerns that have been raised about the prospect of having a whole host of never-before-seen materials introduced into our biosphere. Stay tuned for further discussion.
Conclusion
APM has the potential to deliver the next great technological revolution. While this revolution is not imminent, it does appear to be approaching. When it arrives, it will bring advances to our civilization that will touch on multiple industries and will seem like science-fiction. Moore’s Law will be replaced by a new paradigm in which we can build any structure, atom by atom, across all industries. As a result, the materials we use in the energy, construction, manufacturing and IT sectors will be stronger, free from defects and without waste in their creation. Our ability to solve complex data analysis problems with quantum computers could allow us to discover new drugs in record time and extend the human lifespan dramatically, in addition to addressing numerous other optimization problems. With reliable, atomically precise, high-throughput manufacturing, the heretofore unscalable innovations in nanotech will become scalable and widely proliferated. The improvements to human quality of life from APM’s arrival will dwarf those derived from the previous industrial revolutions, and the scope of the improvements will be across almost every facet of our lives.
Prime Movers Lab invests in breakthrough scientific startups founded by Prime Movers, the inventors who transform billions of lives. We invest in companies reinventing energy, transportation, infrastructure, manufacturing, human augmentation, and agriculture.
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